Pad printing can be used to apply an image to a product. Pad printing may be used in applications for applying images to rounded (e.g., three dimensional) products, such as syringes and sporting equipment. Pad printing is also effective on uneven surfaces, such as the dimpled surface of a golf ball.
Some known pad printing systems use a deformable pad that receives ink, transferred as an image, from a flat cliché plate. The plate has an engraving or etching of the image formed in the plate. The etching of the cliché plate results in recesses in a surface of the cliché plate for receiving or containing ink. The ink is transferred from a liquid supply assembly to the cliché plate where the ink fills the etched recesses. The deformable pad is then pressed onto the plate and ink within the etched recesses is picked up by the pad. The image is then transferred to the print surface by pressing the deformable pad onto the print surface.
To re-ink the pad, an inverted cup that contains a quantity of printing ink may be used to apply additional ink to the cliché plate. The cup and cliché plate are translated relative to each other such that a coating of ink is deposited from the cup onto the cliché plate as the portion of the cliché plate bearing the etched image or indicia travels adjacent (e.g., below) the inverted cup. A doctor blade is fitted to the cup to traverse along the cliché plate and wipe excess ink from the cliché plate. The action of the doctor blade leaves behind the ink that fills the recesses in the etched area of the cliché plate while removing other ink from areas that do not form part of the image (e.g., the ink disposed outside of the etched recesses on the cliché plate) and where the ink may tend to buildup if not removed.
Conventionally, ink is poured from a shipping container, in which the ink was purchased, into a mixing container for mixing of the ink with a quantity of a thinner. The ink is transferred from the mixing container to the ink cup of the pad printing system and the mixing container is discarded. When the ink in the ink cup is depleted, the ink cup is cleaned and refilled. Cleaning of the cup can be costly in terms of the time, labor, and materials required to perform the operation. Additionally, cleaning the cup can involve the handling of potentially noxious substances. Furthermore, the ink that remains in the mixing container is lost, since the remaining ink may be discarded along with the mixing container. Ink also may be potentially lost when the ink is transferred from the mixing container to the cup due to the risk of spillage.
In some known pad printing systems, the ink that is contained within the doctor blade may be insufficient to completely cover the recesses in the etched area. For example, the ink that is moved over the etched area by the doctor blade may not flow into all of the recesses. As a result, not all of the recesses may receive ink and at least a portion of the image to be formed by the recesses may not be formed on the object that receives the ink.
It is desirable to provide a method and system for pad printing that would overcome one or more of the aforementioned and/or other disadvantages.